U.S. patent number 4,248,575 [Application Number 06/007,409] was granted by the patent office on 1981-02-03 for rotary fluid pressure biased vane compressor with pressure release means.
This patent grant is currently assigned to Robert Bosch GmbH. Invention is credited to Naoki Hashizume, Masami Ohtani, Risaburo Watanabe.
United States Patent |
4,248,575 |
Watanabe , et al. |
February 3, 1981 |
Rotary fluid pressure biased vane compressor with pressure release
means
Abstract
A vane compressor includes a hollow stator, and a rotor which is
received in the stator for rotation about an axis. The rotor is
provided with a plurality of throughgoing passages which extend
radially and outwardly relative to the axis. Each passage receives
a vane which has an outer end face directed towards an inner
circumference of the stator and an inner end face directed away
from the inner circumference of the stator. The vanes are shiftable
radially in the respective passages relative to the axis. A
pressure medium is supplied under a first pressure to the inner end
faces of the vanes to urge the same radially outwardly for
engagement of the outer end faces with the inner circumference of
the stator. When the rotor is rotated, the vanes are subjected to
an additional second pressure resulting from centrifugal force. The
second pressure additionally urges the vanes against the inner
circumference of the stator. The first and second pressures
together constitute a cumulative force which above a predetermined
level causes undesired frictional losses at the interfaces between
the outer end faces of the vanes and the inner circumference of the
stator. An arrangement is provided to decrease the cumulative
pressure to the predetermined level to thereby eliminate the
undesired frictional losses.
Inventors: |
Watanabe; Risaburo
(Higashimatsuyama, JP), Ohtani; Masami
(Higashimatsuyama, JP), Hashizume; Naoki
(Higashimatsuyama, JP) |
Assignee: |
Robert Bosch GmbH (Stuttgart,
DE)
|
Family
ID: |
21725979 |
Appl.
No.: |
06/007,409 |
Filed: |
January 29, 1979 |
Current U.S.
Class: |
418/93;
418/269 |
Current CPC
Class: |
F01C
21/0863 (20130101) |
Current International
Class: |
F01C
21/00 (20060101); F01C 21/08 (20060101); F04C
018/00 (); F04C 029/02 (); F04C 029/10 () |
Field of
Search: |
;418/82,93,267-269 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Vrablik; John J.
Attorney, Agent or Firm: Striker; Michael J.
Claims
What is claimed as new and desired to be protected by Letters
Patent is set forth in the appended claims:
1. A vane compressor, comprising a hollow stator having an inner
circumference; a rotor received in said stator for rotation about
an axis, said rotor being provided with a plurality of throughgoing
passages extending radially and outwardly relative to said axis,
said rotor having an outer circumference sealingly contacting said
inner circumference of said stator at least along one contacting
line, said outer circumference of said rotor constituting together
with said inner circumference of said stator at least one working
chamber located between said inner and outer circumferences; a
plurality of vanes, each received in one of said passages and
having an outer end face directed towards said inner circumference
of said stator and an inner end face directed away from said inner
circumference of said stator, said vanes being shiftable radially
in the respective passages relative to said axis; means forming a
high-pressure chamber; means for supplying pressure medium under a
first pressure to said inner end faces of said vanes to thereby
urge said vanes radially outwardly relative to said axis for
engagement of said outer end faces with said inner circumference of
said stator, said pressure medium supplying means including an
annular chamber operatively connected with said high-pressure
chamber so that a pressure in said annular chamber is equal to that
in said high-pressure chamber, said annular chamber being
communicable with said working chamber, said inner end faces of
said vanes communicating with said annular chamber; means for
rotating said rotor about said axis whereby said vanes are
subjected to an additional second pressure resulting from
centrifugal force, which second pressure additionally urges said
vanes against the inner circumference of said stator, said first
and second pressures together constituting a cumulative pressure
which above a predetermined pressure level causes undesired
frictional losses at the interfaces between said outer ends of said
vanes and the inner circumference of said stator; and means for
releasing at least a portion of said pressure medium to thereby
decrease said first pressure by a predetermined value so as to
prevent said cumulative pressure from exceeding predetermined level
and thereby to eliminate said undesired frictional losses, said
pressure releasing means including passage means connecting said
annular chamber with said working chamber, and valve means
operative for movement in said passage means between a first
position in which said annular chamber is disconnected from said
working chamber so as to prevent any pressure medium to flow from
said annular chamber into said working chamber, and a second
position in which said annular chamber is connected with said
working chamber for permitting the pressure medium flow from said
annular chamber into said working chamber, said valve means being
operable in response to increase of centrifugal force thereon
during rotation of said rotor to move from said first position to
said second position.
2. A compressor as defined in claim 1, wherein said vanes engaging
said inner circumference of said stator sealingly divide said
working chamber into a plurality of separate cells.
3. A compressor as defined in claim 1, wherein said valve means
include a valve adapted for releasing said portion of the pressure
medium so as to decrease said first pressure by said predetermined
value, said valve including a valve member.
4. A compressor as defined in claim 3, wherein said passage means
include a passage having one end portion open into said annular
chamber and another end portion open into one of the cells of said
working chamber.
5. A compressor as defined in claim 3, and further comprising
biasing means for urging said valve member into said first
position.
6. A compressor as defined in claim 5, wherein said biasing means
include a spring having two end portions spaced one from the
other.
7. A compressor as defined in claim 6, and further comprising means
for adjusting the biasing force of said spring to thereby adjust
said valve member for movement between said positions in response
to different predetermined levels of the pressure medium in said
annular chamber.
8. A compressor as defined in claim 7, wherein said adjusting means
include a screw cap operative for supporting one end portion of
said spring, the other end portion of said spring abutting said
valve member.
9. A compressor as defined in claim 5, wherein said valve member is
a plug.
10. A compressor as defined in claim 9, wherein said rotor is
provided with an additional throughgoing radially outwardly
extending hole operative for movably receiving therein said
plug.
11. A vane compressor, comprising a hollow stator having an inner
circumference; a rotor received in said stator for rotation about
an axis, said rotor being provided with a plurality of throughgoing
passages extending radially and outwardly relative to said axis,
said outer circumference of said rotor constituting together with
said inner circumference of said stator at least one working
chamber located between said inner and outer circumferences, said
rotor being provided with an additional throughgoing radially
outwardly extending hole; a plurality of vanes, each received in
one of said passages and having an outer end face directed towards
said inner circumference of said stator and an inner end face
directed away from said inner circumference of said stator, said
vanes being shiftable radially in the respective passages relative
to said axis; means forming a high-pressure chamber; means for
supplying pressure medium under a first pressure to said inner end
faces of said vanes to thereby urge said vanes radially outwardly
relative to said axis for engagement of said outer end faces with
said inner circumference of said stator, said pressure medium
supplying means including an annular chamber operatively connected
with said high-pressure chamber so that a pressure in said annular
chamber is equal to that in said high-pressure chamber, said
annular chamber being communicable with said working chamber, said
inner end faces of said vanes communicating with said annular
chamber; means for rotating said rotor about said axis whereby said
vanes are subjected to an additional second pressure resulting from
centrifugal force, which second pressure additionally urges said
vanes against the inner circumference of said stator, said first
and second pressures together constituting a cumulative pressure
which above a predetermined pressure level causes undesired
frictional losses at the interfaces between said outer ends of said
vanes and the inner circumference of said stator; and means for
releasing at least a portion of said pressure medium to thereby
decrease said first pressure by a predetermined value so as to
prevent said cumulative pressure from exceeding said predetermined
level and thereby to eliminate said undesired frictional losses,
said pressure releasing means including passage means connecting
said annular chamber with said working chamber, and valve means
operative for movement in said passage means between a first
position in which said annular chamber is disconnected from said
working chamber so as to prevent any pressure medium to flow from
said annular chamber into said working chamber, and a second
position in which said annular chamber is connected with said
working chamber for permitting the pressure medium flow from said
annular chamber into said working chamber, said valve means
including a valve adapted for releasing said portion of the
pressure medium so as to decrease said first pressure by said
predetermined value, said valve including a valve member and
biasing means operative for urging said valve member into said
first position and including a spring having two end portions
spaced one from the other, said valve member being a plug which is
movably received in said additional radial hole of said rotor, and
said additional radial hole being closed from the outside by a
closing member operative for supporting one end portion of said
spring.
12. A compressor as defined in claim 11, wherein said valve member
is a hollow cylindrical plug.
13. A vane compressor, comprising a hollow stator having an inner
circumference; a rotor received in said stator for rotation about
an axis, said rotor being provided with a plurality of throughgoing
passages extending radially and outwardly relative to said axis,
said rotor having an outer circumference sealingly contacting said
inner circumference of said stator at least along one contacting
line, said outer circumference of said rotor constituting together
with said inner circumference of said stator at least one working
chamber located between said inner and outer circumferences; a
plurality of vanes, each received in one of said passages and
having an outer end face directed towards said inner circumference
of said stator and an inner end face directed away from said inner
circumference of said stator, said vanes being shiftable radially
in the respective passages relative to said axis; means forming a
high-pressure chamber; means for supplying pressure medium under a
first pressure to said inner end faces of said vanes to thereby
urge said vanes radially outwardly relative to said axis for
engagement of said outer end faces with said inner circumference of
said stator, said pressure medium supplying means including an
annular chamber operatively connected with said high-pressure
chamber so that a pressure in said annular chamber is equal to that
in said high-pressure chamber, said annular chamber being
communicable with said working chamber, said inner end faces of
said vanes communicating with said annular chamber; means for
rotating said rotor about said axis whereby said vanes are
subjected to an additional second pressure resulting from
centrifugal force, which second pressure additionally urges said
vanes against the inner circumference of said stator, said first
and second pressures together constituting a cumulative pressure
which above a predetermined pressure level causes undesired
frictional losses at the interfaces between said outer ends of said
vanes and the inner circumference of said stator; and means for
releasing at least a portion of said pressure medium to thereby
decrease said first pressure by a predetermined value so as to
prevent said cumulative pressure from exceeding said predetermined
level and thereby to eliminate said undesired frictional losses,
said pressure releasing means including passage means connecting
said annular chamber with said working chamber, and valve means
operative for movement in said passage means between a first
position in which said annular chamber is disconnected from said
working chamber so as to prevent any pressure medium to flow from
said annular chamber into said working chamber, and a second
position in which said annular chamber is connected with said
working chamber for permitting the pressure medium flow from said
annular chamber into said working chamber, said pressure releasing
means also including means for preventing backflow of the pressure
medium from said working chamber into said annular chamber through
said passage means.
14. A compressor as defined in claim 13, wherein said backflow
preventing means include a check valve mounted in said passage
means for permitting said pressure medium to flow from said annular
chamber into said working chamber and preventing said pressure
medium to flow from said working chamber into said annular
chamber.
15. A compressor as defined in claim 14, wherein said check valve
is so located in said passage means as to eliminate any influence
of said centrifugal force on the operation of said check valve.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a compressor.
More particularly, the present invention concerns a vane
compressor.
It is known in the prior art to provide a vane compressor with a
rotor rotatably mounted in a stator. The rotor has a plurality of
throughgoing passages which extend radially and outwardly relative
to an axis of the rotor. Each passage receives a vane which has an
outer face directed towards an inner circumference of the stator
and an inner face which is directed away from the inner
circumference of the stator. The vanes are shiftable radially in
the respective passages relative to the axis. A pressure medium is
supplied under a first pressure to the inner end faces of the vanes
to thereby urge the latter radially outwardly relative to the axis
of the rotor for engagement of the outer end faces of the vanes
with the inner circumference of the stator. When the rotor rotates
the vanes are subjected to an additional second pressure resulting
from centrifugal force. The second pressure additionally urges the
vanes against the inner circumference of the stator. The first and
second pressures together constitute a cumulative pressure which
when above a predetermined level causes undesired frictional losses
at the interfaces between the outer ends of the vanes and the inner
circumference of the stator.
SUMMARY OF THE INVENTION
It is a general object of the present invention to avoid the
disadvantages of the prior art vane compressors.
More particularly, it is an object of the present invention to
provide such a vane compressor which does not cause any undesired
frictional losses between the vanes and the inner circumference of
the stator even when the rotor rotates with a high rotational
speed.
Another object of the present invention is to provide a vane
compressor with an arrangement to decrease the pressure onto the
vanes when the rotational speed exceeds a predetermined level to
thereby maintain the cumulative radial force urging the vanes into
engagement with the inner circumference of the stator on such a
level as to avoid any frictional losses between the vanes and the
inner circumference of the stator.
Still another object of the present invention is to release a
corresponding amount of a pressure medium from the interior of the
rotor when the rotational speed of the same increases, to thereby
maintain the cumulative radial force, urging the vanes into
engagement with the inner circumference of the stator, at a
predetermined level so as to avoid any frictional losses between
the vanes and the inner circumference of the stator.
In pursuance of these objects and others which will become apparent
hereafter, one feature of the present invention resides in
providing a hollow stator with a rotor for rotation about an axis.
The rotor is provided with a plurality of throughgoing passages
which extend radially and outwardly relative to said axis. Each
passage receives a vane which has an outer end face directed
towards an inner circumference of the stator and an inner end face
directed away from said inner circumference of said stator. The
vanes are shiftable radially in the respective passages relative to
said axis. There are further provided means for supplying pressure
medium under a first pressure to the inner end faces of said vanes
to thereby urge the latter radially outwardly relative to said axis
for engagement of said outer end faces with said inner
circumference of the stator. The rotor is rotated about said axis
whereby the vanes are subjected to an additional second pressure
which results from centrifugal force. The second pressure
additionally urges the vanes against the inner circumference of the
stator. The first and second pressures together constitute a
cumulative pressure which when above a predetermined pressure level
causes undesired frictional losses at the interfaces between the
outer end faces of said vanes and the inner circumference of the
stator.
One of the main advantageous features of the present invention
resides in providing means for releasing at least a portion of said
pressure medium to thereby decrease said first pressure by a
predetermined value so as to prevent said cumulative pressure from
exceeding said predetermined level and thereby to eliminate said
undesired frictional losses.
The novel features which are considered as characteristic for the
invention are set forth in particular in the appended claims. The
invention itself, however, both as to its construction and its
method of operation, together with additional objects and
advantages thereof, will be best understood from the following
description of specific embodiments when read in connection with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a longitudinal section of a vane compressor in accordance
with the present invention, taken along the line 1--1 in FIG.
2;
FIG. 2 is a sectional view of the vane compressor, turned relative
to the view of FIG. 1; and
FIG. 3 is an enlarged view of a portion of another embodiment of
the vane compressor.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to the drawings and first to FIGS. 1 and 2 thereof,
it may be seen that the reference 25 designates a cylindrical
stator which has a cylindrical interior 12. The both end openings
of the stator 25 are closed by end face plates 38 and 40,
respectively. The plates 38 and 40 are rigidly fixed (i.e. screwed
on) on the end faces of the stator 25 so as to axially limit the
interior 12 thereof. A rotor 15 is mounted in the interior 12 of
the stator 25 for rotation relative thereto. The rotor 15 includes
a circular cylindrical casing which sealingly engages the inner
circumference of the stator 25 along two diagonally oppositely
located lines of the inner circumference of the casing. Between the
outer circumference of the rotor 15 and the cylindrical inner
circumference of the stator 25 there are located two opposite
crescent-shaped working chambers.
The central hole of the rotor 15 receives the end portion of a
shaft 17 which is supported on two sliding bearings which are
located in a hollow supporting tube of a left end face plate 40.
The shaft 17 extends with its portion outwardly away from the plate
40 and is sealed by a conventional shaft sealing arrangement 19.
The stator 25 with the end face plates 38 and 40 is encompassed by
a cup-shaped closure 4, which is mounted on a base 46 by means of
screws 26 and contains liquid whose level is identified by
reference letter D. The base 46 is in its turn connected to the
stator 25 by means of screws 27.
The base 46 is provided with a low pressure chamber 47 which has a
connecting pipe 22 having a suction valve 20. The low pressure
chamber 47 also is connected to a hose (not shown) connected to a
source of the pressure medium (e.g. liquid), for example, of a
refrigerating circuit of a vehicle conditioning arrangement. The
pressure in the low pressure chamber 47 corresponds to that in the
vane cells of the vane compressor.
The space between the stator 25, with the plates 38 and 40, and the
closure constitutes a high-pressure chamber 36 of the vane
compressor. The chamber 36 is connected with the interior 12 of the
stator 25 by means of a coagulating filter 37 which separates the
pressure medium from oil. The reference numeral 1 is used to
designate an outlet from the high-pressure chamber 36 (see FIG.
2).
It may be seen from FIG. 2 that the working chambers, located
between the outer circumference of the rotor 15 and the inner
circumference of the stator 25, have a somewhat crescent-shaped
configuration. Each working chamber has a low-pressure section and
a high-pressure section. The low pressure section of each working
chamber communicates with the low pressure chamber 47 in the base
46 by means of a low-pressure passage 10 in the stator 25. Each
high-pressure section of the working chamber is connected through a
conveying passage 16, which is provided with a plate valve 6, with
a space bounded by a closure 7. This space is connected through a
channel 8 to the coagulating filter 37, and hence to the
high-pressure chamber 36.
The rotor 15 is provided with a plurality of throughgoing passages
14, which extend radially and outwardly relative to a longitudinal
axis A of the rotor 15. Each passage 14 sealingly receives a vane
11, which has an outer end face directed towards the inner
circumference of the stator 25 and an inner end face directed away
from the inner circumference of the stator 25. The vanes 11 are
shiftable radially in the respective passage 14 relative to the
axis A. The outer end faces of the vanes 11 engage the inner
cylindrical circumference of the stator 25 so as to divide the
respective working chambers in separate cells.
A shaft 17 is provided with an integrally connected thereto flange
17a which is received in the corresponding recess of the rotor 15.
The shaft 17 is connected with conventional driving member (e.g. a
motor) which is not shown for the sake of simplicity of the
drawing. Concentrically with the rotor there is provided an annular
chamber 48 which is connected through a channel 21 with the high
pressure chamber 36. The channel 21 is rather narrow, so that it
functions as a throttle. It is also possible to arrange a separate
throttle in the channel 21 so as to prevent the pressure medium
flow from the high-pressure chamber 36 into the chamber 48. The
inner end face of the passages 14 is open into the chamber 48. The
pressure in the chamber 48 and in the inner end portions of the
passage 14, which are sealingly closed from outside by the vanes
11, is equal to that in the high-pressure chamber 36.
The rotor 15 is provided with another throughgoing radial passage
41 which receives a valve 3, which is actuated in response to
centrifugal force of a predetermined value. When the valve 3 is
open the pressure medium is released from the chamber 48 and
therefore from the inner end portion of the passage 14 into one of
the above-mentioned cells of the working chambers. The valve 3
includes a hollow cylindrical sliding plug 34 slidably mounted in
the passage 41. The plug is movable between a closed position in
which it closes the passage 41 from the cell (FIG. 1) and an open
position in which it opens the passage 41 for communication through
a passage 31 with the cell. A spring 33 is mounted with its one end
portion on the plug 34 and with its other end portion it abuts a
cap 32 (e.g. a screw cap) so as to normally urge the plug 34 in the
closed position. A check valve 39 is placed in the passage 31, so
as to permit the liquid flow from the chamber 48 into the cell of
the working chamber but to prevent the liquid flow in the opposite
direction, i.e. from the cell into the chamber 48. The check valve
39 is so located in the passage 31 that the centrifugal force has
no influence whatsoever onto the function of the check valve 39.
The outlet of the passage 31 is advantageously located adjacent the
vane 14 in a direction X of rotation of the rotor 15.
The vane compressor works as follows: During rotation of the rotor
15 in a direction X (see FIG. 2) the working chamber, including two
adjacent cells separated one from the other by the respective
vanes, increases at first (low-pressure sector) and then decreases
(high-pressure sector). During the increasing phase each cell of
the working chamber is connected with the low-pressure passage 10,
so that the pressure medium flows into the cells. Later, the cell
separated by the vanes 11 decreases, so that the pressure medium in
this cell is compressed. The compressed pressure medium flows
through the plate valve 6 into the coagulating filter 37 and
further into the high-pressure chamber 36. The oil separated from
the pressure medium by the coagulating filter 37 is accumulated in
the lower area of the high-pressure chamber 36 and flows through a
channel (not shown) into the opening 10, in the interior 12 of the
stator 25, in the chamber 48, and further into the passages 14.
Thus, the oil lubricates all movable parts of the vane
compressor.
The high pressure in the chamber 48--corresponding to that in the
high-pressure chamber 36--urges the vanes 11 radially and outwardly
relative to the axis A into engagement with the inner circumference
of the stator 25. During rotation of the rotor 15 each vane 11 is
subjected to an additional pressure resulting from centrifugal
force, which depends on the rotational speed (i.e. number of
revolutions) of the vane compressor. Obviously, the sliding plug 34
of the valve is subjected to the same centrifugal force. As the
rotational speed of the rotor increases, the centrifugal force
increases correspondingly. When the centrifugal force exceeds the
biasing force of the spring 33, the plug 34 moves in the open
position against the biasing force of the spring 33 until the
passage 41 can communicate with the channel 31. A pressure medium
may flow from the chamber 48 into the passage 31 and further into
the cell of the working chamber during each intake stroke. Thus,
the cumulative force acting on the inner end face of the vanes 11
decreases, correspondingly. The pressure in the chamber 48 is
stipulated by the length and cross-sectional size of the channel
31. The vanes 11 are urged against the inner circumference of the
stator 25 substantially only by the centrifugal force.
The weight of the slidable plug 34 is so big, that when the
rotational speed of the rotor gets to a predetermined level the
sliding plug 34 starts to slide downwardly towards the closed
position. It is to be noted, that the pressure differential between
the pressure on the side of the plug, which is directed towards the
chamber 48 and the pressure on the opposite side of the plug should
be maintained relatively small.
It is to be understood that there may be provided at least two such
valves 3, that is one at the front side and another at the rear
side of the vane 11. Should it be the case, then one can obtain
substantially constant pressure on the vanes 11 during rotation of
the rotor 15.
FIG. 3 shows another embodiment of plug 34' as opposed to the plug
34 shown in FIG. 1. The plug 41' has a cup-shaped cross-section. In
other respects the plug 34' shown in FIG. 3 functions similar to
that shown in FIG. 1.
It will be understood that each of the elements described above, or
two or more together, may also find a useful application in other
types of a vane compressor differing from the types described
above.
While the invention has been illustrated and described as embodied
in a vane compressor it is not intended to be limited to the
details shown, since various modifications and structural changes
may be made without departing in any way from the spirit of the
present invention.
Without further analysis, the foregoing will so fully reveal the
gist of the present invention that others can, by applying current
knowledge, readily adapt it for various applications without
omitting features that, from the standpoint of prior art, fairly
constitute essential characteristics of the generic or specific
aspects of this invention.
* * * * *